Which of the following is defined as a field that contains a unique value for each record? 1. Unique Field 2. New Field 3. None of the above 4. Primary Key

The concept you are asking about pertains to database management. In a database, a field that contains a unique value for each record is known as a Primary Key.

Explanation:

1. Unique Field: This is not a standard term widely recognized in database terminology.
2. New Field: This term generally does not imply uniqueness; it just refers to any newly created field.
3. None of the above: This option is incorrect since there is a valid answer.
4. Primary Key: This is a field (or a set of fields) that uniquely identifies each record in a table. Hence, no two records can have the same value in this field.

Therefore, the correct answer is 4. Primary Key.